Slaves are cheap these days. Their price is the lowest it's been in about 4,000 years. And right now the world has a glut of human slaves - 27 million by conservative estimates and more than at any time in human history.

Although now banned in every country, slavery has boomed in the past 50 years as the global population has exploded. A billion people scrape by on $1 a day. That extreme poverty combined with local government corruption and a global economy that leaps national boundaries has produced a surge in the number of slaves - even though in the developed world, that word conjures up the 19th century rather than the evening news.

"For an American audience, their conceptualization of slavery is locked into a picture from the past," says Kevin Bales, president of Free the Slaves (www.freetheslaves.net), a nonprofit in Washington. "It's fixed in the slavery of the deep South and it's about African-Americans being enslaved on plantations with chains and whips and so forth."

Modern-day slavery has little of the old South. Of those 27 million, the majority are bonded laborers in India, Pakistan, Bangladesh, and Nepal - workers who have given their bodies as collateral for debts that never diminish no matter how many years, or sometimes generations, the enslaved labor on. Cooking the books is an early lesson for slaveholders.

Yet despite this new largely unacknowledged slavery epidemic, Dr. Bales is optimistic. While the real number of slaves is the largest there has ever been, he says, it is also probably the smallest proportion of the world population ever in slavery. Today, he adds, we don't have to win the legal battle; there's a law against it in every country. We don't have to win the economic argument; no economy is dependent on slavery (unlike in the 19th century, when whole industries could have collapsed). And we don't have to win the moral argument; no one is trying to justify it any more.

The fact that it's still thriving, he explains, comes down principally to ignorance about the institution and lack of resources directed at eradicating it.

Lack of public awareness is strikingly apparent in developed countries, where few are conscious that it is not exclusively a third-world problem.

Although the numbers are small relative to the worldwide challenge, in the developed world slavery happens uncomfortably close to home. For instance, between 14,000 and 17,500 people are trafficked into the United States annually, according to the US government, most forced into the sex trade, domestic servitude, or agricultural labor. At any one time, between 52,000 and 87,000 are in bondage. And much of that is in plain view, in towns and cities across the country, experts say. People simply don't recognize it.

In June, an Indian domestic in Brookline, Mass., won a court case against an Omani couple who had barred her from leaving their apartment unescorted for more than a year, forcing her to look after their four children, cook, and clean without proper pay or meals. An alert neighbor who caught wind of her plight helped her escape.

But that is the exception, suggests Tommy Calvert of American Anti-Slavery Group in Boston. "Law enforcement and legal professionals don't always identify a victim of slavery as such." And the public is even less likely to recognize the signs.

Last month, the State Department issued a fact sheet urging citizens "to help end modern-day slavery" and warned "it may even be happening in their own backyards."

It's where domestic violence was 35 years ago, Bales say. No one talked about it, no shelters existed, and no one had written a pamphlet laying out what it looked like.

That's about to change. A pamphlet on slavery is in the works, says Bales, who hopes to get it distributed to neighborhood watch groups around the US before the end of the year, if funding comes through. The draft, titled "How can I recognize trafficking victims" includes a list of "visible indicators" of whether an establishment is holding people against their will and the physical signs that a person might be enslaved. Once people are better informed, he expects a flood of cases.

Part of the confusion about slavery, says Bales, is that it has evolved over the centuries and what we traditionally thought of as slavery - chattel slavery - looks very different these days. But the definition remains the same: "Slavery is the status or condition of a person over whom any or all of the powers attaching to the right of ownership are exercised" (Slavery Convention of the League of Nations, 1926).

In his book "Disposable People," Bales says ownership is no longer an attractive proposition for most slaveholders because the price of slaves is so low. In 1850, a slave would cost about $40,000 in today's dollars. Now, you can buy a slave for $30 in the Ivory Coast. The glut "has converted them from being the equivalent of buying a car to buying a plastic pen that you use and throw away," he says. That makes maintenance of the "investment" a low priority, and little care is taken for slaves' well-being.

The most common type of slavery is debt bondage which traps 15 million to 20 million in loan agreements they can never pay off. Others are lured by false promises into forced labor situations, where they are coerced to stay under threat of violence. Slavery also includes the worst forms of child labor and sexual exploitation of women and girls.

The fastest growing type, however, is trafficking ("forcing and transporting people into slavery"). According to a Department of Justice report in June on human trafficking, 600,000 to 800,000 people are trafficked across national borders each year (and millions more are trafficked within their own countries). Of those, about 80 percent are female, and an estimated 70 percent end up in the commercial sex trade, the report says. The United Nations estimates that the profits from human trafficking (about $9.5 billion last year) rank it among the top three revenue earners for organized crime, after drugs and arms. In 10 years, it's expected to be the top source of revenue.

This rapid rise has been met with new laws in the US (the Trafficking Victims Protection Act 2000, which was reauthorized and expanded last December), a rapid ratification of the UN Convention against Transnational Organized Crime put forward in 2000, which also came into force last December, and greater sharing of information and coordination among nations to combat trafficking.

The UN declared 2004 International Year to Commemorate the Struggle Against Slavery and its Abolition, even though, ironically, there are more slaves now than there were even at the height of the transatlantic slave trade.

Enforcement is one stalling point in its eradication. A Human Rights Watch report issued in July, for instance, looks at the pattern of exploitation of foreign domestic workers in Saudi Arabia. Although the Saudis are held to account for a judicial system that makes its almost impossible for foreign nationals to appeal their circumstances, says Sarah Leah Whitson, executive director of Middle East and Africa for HRW, the sending countries shirk their responsibilities, too. "They need to better protect their nationals," she says. "Unfortunately, each one [of the sending countries] says, if we make it tough for Saudi [Arabia] then they will just go to Pakistan [for foreign workers]. And Pakistan says, if we make it tough, then they will just go to the Philippines. So it's a race to the bottom."

Even when law enforcement is not in question, uncovering cases can be like looking for clues in the dark. Last year, only nine trafficking cases were prosecuted in the US with a total of 17 convictions - the smallest sliver of those working the new slave trade. "The thing that is unique about human trafficking and enslavement," says Bales "... is that it's a crime of seriousness equal to kidnapping, torture, murder etc. and yet it has the 'dark figure' [a criminologist's term for crimes that remain hidden, unreported] of bicycle theft."

The conditions of those enslaved are usually filled with physical and mental abuse and violence - or at least the constant threat of it - and sometimes unimaginable deprivations. Girls are frequently "broken in" to the profession of prostitution, for instance, through beatings and rape, and if they are rebellious, they may end up dead. Long hours, sometimes 15 or more a day, with no days off, privacy, or adequate food are common.

For those who escape servitude, the road to freedom can be uncertain. A UN fact sheet on contemporary slavery hints it may be easier to free the body than the mind: "Even when abolished, slavery leaves traces. It can persist as a state of mind - among its victims and their descendants and among the inheritors of those who practiced it - long after it has formally disappeared."

To see what happens when a country does no more than liberate its slaves, says Bales, look at the US. "It had one of the largest botched emancipations in human history. Four million people dumped into the economy without any kind of tools, capital, education, political participation, rehabilitative care. Nothing. And we're still paying the price."

Rehabilitation, as crucial as it is, is still an infant science. Lone individuals like Vivek and Vidyullata Pandit in northern India, a husband-and-wife team, have developed their own system of rehabilitation for bonded laborers. But more universal treatment protocols are perhaps years off. Currently, programs adapt models used for victims of torture or domestic violence.

"Bondage can be compared to living in a prison or a mental institution," Bales writes in "Disposable People." "Those who get out have to learn about living in the 'real world.' "

And sometimes, freed slaves do return to their slaveholders, unable to cope outside the strict confines of their former existence.

"The three most important things people need to fight bonded labor," says Vidyullata Pandit on the website of the Unitarian Universalist Church, which funds their work, "are knowledge of the law, self-confidence to bring about change, and ... conviction to ensure they don't go back to bonded labor once they are released."

• Next Tuesday, Sept. 7: An inside look at how Brazilian antislavery police break up a logging ring in the Amazon rainforest.

How a young boy was enslaved

NEW YORK - Next to laughing bathers on Coney Island where he works as a lifeguard, Simon Deng tells the story of his past - a story from a different universe. As a child, Mr. Deng was a slave for two years.

Born into a large family in southern Sudan, Deng was raised Christian. He describes his village of Tonga as a "peaceful farming community," yet he remembers frequent raids by Muslim Sudanese in army trucks from the north, burning huts and scattering livestock.

"One of the first things I was told ... if the Arab men come, just run, run for your life," Deng recalls.

One day, at the age of 8 or 9, Deng was helping a stranger from the north load packages onto a boat. The next thing he knew, he was captive in a small cabin as the boat headed for Khartoum, the nation's capital. There, the stranger sold Deng and several other boys to wealthy families.

Deng spent the next two years with the family about 200 miles northwest of Khartoum. As a domestic servant, he tended their donkeys and goats, cleaned, washed dishes, and hauled massive barrels of water up from the river several times a day. He slept in straw in the corner of the kitchen, was rarely given enough food, and endured regular beatings.

Like the majority of families in northern Sudan, Deng's "owners" were Muslim, and they often urged him to convert to Islam. They told him that if he did so they would accept him as their own son, but he refused. At the age of 11, Deng escaped with the aid of a man he knew from his hometown. He went on to work as a messenger in the Sudanese parliament and later to become a national swimming champion.

Today, Deng still has scars from boyhood beatings (although the marks on his face are cosmetic). He devotes his time to working with worldwide antislavery groups. He says he cannot remain silent. "I thought I could forget and forgive," Deng says. "But villages are still being burnt, women are still being raped, and people are being sold into slavery."